1. Field of the Invention
The present invention generally relates to a method for manufacturing a magnetic head suspension assembly used for a magnetic disk unit or the like. More particularly, the present invention relates to a method for manufacturing a magnetic head suspension assembly wherein a wiring member for connecting a magnetic head element with a read/write amplifier circuit board is integrally formed with a suspension.
2. Description of the Related Art
Magnetic disk units of the type with which the present invention is suited for use are equipped with at least one rotary disk for magnetically recording information, a magnetic head element, for reading from or writing to tracks on the disk, and a head positioning actuator which is connected with the head element. The positioning actuator is used to move the head element to a desired track and maintain the head element above the selected track.
An example of a conventional magnetic head suspension assembly is disclosed in published Japanese Patent Application No. 63-113917. In this art, the magnetic head element is attached to a flexure by epoxy resin or the like and the flexure is installed on a load beam by laser welding or the like. Gold-plated copper lead wire provided with urethane coating or the like is connected by ultrasonic bonding, soldering, or the like to electrodes on the magnetic head element, thus forming a leader wiring section for sending a signal from the magnetic head to an external circuit. The wiring member is turned a number of times before it is housed in a flexible insulating resinous tube, and mounted on the suspension by crimping a part of the suspension or other similar means.
The above-identified prior art magnetic head suspension assembly suffers from the problem that forming the connection between an electrode on the magnetic head element and the leader wiring is extremely inefficient due to restrictions on operability, making it difficult to achieve higher productivity. This problem has been exacerbated by the increasing number of terminals resulting from the reduced sizes of magnetic head elements and the increasing use of MR elements in recent years. Furthermore, an additional problem arises because the rigidity of the leader wiring member prevents the magnetic head element from obtaining an optimum position when it floats. A final problem with this prior art suspension is that the leader wiring member is subjected to wind pressure from air flow produced by a rotating recording medium, which disturbs the position of a floating magnetic head element.
In an attempt to solve the above-discussed problems, as shown in published Japanese Patent Application No. 53-74414, it has been proposed to employ a flexible circuit board, which serves as the leader wiring member and the suspension mechanism, to support the magnetic head element. This approach however, presents many problems in achieving accurate positioning, applying the appropriate load, and achieving the appropriate floating position of the magnetic head element.
As another approach to solving the problems discussed above which are associated with conventional leader wiring, a flexible circuit board, which includes all wiring, is attached to a suspension spring with an adhesive agent or the like. This approach, however, unavoidably trades-off weight reduction for operability because a separate flexible circuit board must be glued to the suspension spring. This is contrary to the principal that a member which serves as a servo mechanical element should be as light weight as possible to meet the demand for faster seek, etc.
Hence, there has been a demand for a magnetic head suspension assembly which reduces the adverse influences on the floating position of the magnetic head exerted by the leader wiring member and also permits easier mounting of the magnetic head element,these improvements being achieved by combining the leader wiring member and the suspension into one piece.